1. Technical Field
This invention relates to a rotary electric machine such as an electric motor for use in an electric two-wheeler or the like, and particularly to a rotary electric machine of high productivity/maintainability.
2. Background Art
In recent years, an axial gap type electric motor is used on a rear axle of an electric two-wheeler, as a power source. Such a motor includes a stator fixed to a rear arm extending from a body frame, and a rotor rotating with respect to the stator for transmitting power to a rear wheel.
The rotor is configured such that a magnetic pole-carrying face and a shaft portion supported for rotation by a bearing are joined together, and transmits power to the rear wheel through a one-way clutch for the prevention of overcharging of the battery and for the mitigation of push and walk load.
Also, when magnetic poles are bonded on the yoke in a production process, the magnetic poles are mounted on the yoke to which is applied an adhesive, and they are pressed against the yoke for regulation such that their heights are set ideal.
As described above, a yoke of a rotor in an axial motor for an electric two-wheeler is configured such that a magnetic pole-carrying face and a shaft portion supported for rotation by a bearing are joined together, therefore production control is required for the processes such as welding or the like, or for each part, which lowers productivity and as a result, production costs are increased.
Also, the yoke of the rotor doesn't have a shape allowing accommodation of a one-way clutch, so that the lateral dimension of the rear wheel becomes wider, the air resistance becomes greater and further, the freedom of designing is decreased.
Also, the stator coil, when not being energized, is attracted by the magnetic poles of strong magnetic force, so that it is not easy to remove the rotor at the time of maintenance or the like of the electric two-wheeler.
Also, when magnetic poles are attached to the yoke, only the magnetic poles are pressed against the yoke, so that variations in the height of the magnetic poles are produced and a desired gap is difficult to be provided between the magnetic poles and the stator. Therefore, this results in a drop in productivity.
Such difficulties are true for rotary electric machines including generators.
In view of the foregoing, an advantage of this invention is to provide a rotary electric machine of high productivity/maintainability.